The mission of the Characterization and Formulation Core is to provide support to Projects 1, 2 and 3 by: 1) developing simple formulations; 2) performing sperm function inhibition tests; 3) evaluating their safety/toxicity potential; and 4) developing clinically advantageous formulations. Agents will be prioritized based on their in vitro antimicrobial properties (Projects 1 and 2). Simple formulations whose bases are inactive will be developed for high priority compounds and tested in animal models (Project 3). Sperm function inhibition tests will characterize the compounds as potential noncontraceptive and contraceptive antimicrobials. Based on these results as well as other considerations, the compounds will be reprioritized. Initial safety/toxicity studies will be performed with the most desirable compounds. Those which appear safe will be considered candidates for pre-IND development and clinical trial. Clinically advantageous formulations will be developed which should further increase and maximize the antimicrobial properties of the compounds. The outcome of this work will be the availability of novel, tentatively safe and potentially clinically useful active ingredients/formulations for further preclinical development.